1. Field of the Invention
The present invention relates to an imaging lens and an electronic apparatus having the same, more particularly to an imaging lens with four lens elements and to an electronic apparatus having the same.
2. Description of the Related Art
In recent years, various electronic devices are designed to include imaging lenses and image sensors for image-capturing and video-recording capabilities. To improve portability and imaging performances while reducing dimensions and weights of the electronic devices, different combinations of lenses are installed in the electronic devices.
U.S. Pat. No. 7,453,654 discloses an imaging lens with four lens elements of different optical characteristics, one of which is a spherical glass lens element while remaining three of which are plastic aspherical lens elements for enhancing image quality. However, the spherical glass lens element is difficult to fabricate due to its small dimensions and radius of curvature, and therefore has drawbacks such as high costs and weight.
Besides, although the spherical glass lens element is able to achieve a relatively high positive refracting power at a relatively small radius of curvature such that an overall length of the imaging lens may be significantly reduced, the spherical glass lens element is known to exhibit high chromatic aberration due to its low Abbe number.
U.S. Pat. No. 6,476,982 discloses an imaging lens with first and second lens elements thereof adhesively bonded to each other to thereby reduce chromatic aberration. Nevertheless, such an approach to reduce chromatic aberration requires a strong bonding between the first and second lens elements, which is often difficult to achieve especially if the first and second lens elements are made of different materials, e.g., glass and plastic, respectively. While the first and second lens elements may both be made of glass, costs and weight of the imaging lens will, as a result, be compromised.
U.S. Pat. No. 7,466,497 discloses an imaging lens with four plastic lens elements. Although the imaging lens has a relatively short overall focal length and may be fabricated at a relatively low cost, the imaging lens is known to exhibit high chromatic aberration.
Therefore, the need for a low cost, low weight imaging lens that exhibits low chromatic aberration still exists in the market.